Assemling Locomotive Wheels

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Wheel Assembly

This one aspect of the hobby that takes a lot of patience as much as wheel turning or track laying. If you have come this far then your skills have been tested and your patience has been proven cause you will need a lot of it. Assembling standard Diesel and Electric locomotive wheels is very easy. Just press fit , measure and you are ready to go. However steam and other locomotives that utilize drive rods to drive their wheels are a whole different ball game altogether.

Some of the tools needed for assembling wheels are...

Wheel Pullers
Wheel Press
NMRA/NEM Gauge
Quartering tool
Pressure-tins to fit appropriate wheel diameters for press tool

Step 1: Assemble all the wheels without the insulating plug onto the axles. Use a wheel press to press-fit the axles into the wheel. This will ensure that the axle fits into the wheel absolutely perpendicular. Install these axles and wheel combinations into the locomotive. You now have one side of the locomotive with wheels. With Märklin locomotives this will typically be the geared wheels (right side). With this we will also assume that the locomotive body will be the same polarity as these wheels. I personally prefer to keep the right rail as the body. It is your preference really but keep it consistent across all your locomotives. Note it is preferred to install the wheels with metal hubs first.

Skip step 2 if you are working on a locomotive that does not have drive rods such as most diesels or electric locomotives.

Step 2: Quartering the wheels - This step is the most crucial step for steam and other locomotives that have drive rods. All such wheel sets are 90^o offset. Using a quartering tool align the crank pin of the assembled wheel with the vertical cross hair and adjust the opposite wheel 90^o to the vertical. Make sure every wheel is offset in the same direction. Try and be as accurate as possible. There are different types of quartering tools to accomplish the same job. I prefer the prism-type Fohrmann tool as it can accommodate wheels that need to be assembled directly into locomotives. The NWSL tool is also very good and significantly more easy to use but is meant for wheel sets that can be disengaged from the locomotive body ( like Roco and most American models) compared to Märklin, Fleischmann, etc.

Step 3: Press Fit - Once you align the wheels just gently press fit and then use a wheel press tool with the appropriate diameter pressure-tin and complete the job. You can also use the lathe as a press by mounting the appropriate pressure-tin on a press pin and use the tail stock as a press.

Step 4: Measure the finished axle with the NMRA/NEM gauge and adjust appropriately.

Step 5: Touch up and weather - Chipped paint and scuff marks are unavoidable. This is easily touched up with RAL 3002 paint and then weathered by just adding a few drops of the black wash (see weathering) and you should be pretty much done. Try rotating the wheels and make sure they turn smoothly. If you find they snag in a particular position or even a small lift in any wheel then that particular wheel is slightly out of phase and adjust appropriately till you get very smooth rotation.